#!/usr/bin/perl
use strict;
use warnings;

# Ivan Novick
# grep.pl
# demonstrate the perl grep function to select members of an array

my @fruits = ('apple', 'banana', 'cranberry', 'date', 'elderberry', 'fig', 'grape');

# grep for all fruits that end in the letter 'e' 
# return result as a new array
my @some_fruits = grep { /e$/ } @fruits;

# print out the fruits that were greped out of the original array
for my $f (@some_fruits)
{
    print "match: $f\n";
}
print "=======================================================\n";

# create an array of numbers from 1 to 100
my @nums = (1 .. 100);

# grep out all numbers that are divisible by 9
my @some_nums = grep { $_ % 9 == 0 } @nums;

for my $n (@some_nums)
{
    print "match: $n\n";
}
print "=======================================================\n";

# a more complex multi-statement grep
my @more_fruits = grep 
{
    my $fruit = $_;
    my $string_match = 0;
    my $length_match = 0;

    $string_match = 1 if ( $fruit =~ /a/ );
    $length_match = 1 if ( length($fruit) > 5 );

    # the result of grep is determined by the value of the last statement
    # in this case the last statement is a logical AND so both variables must evaluate to true
    # this implies that the fruit contains the letter 'a' and is greater than 5 characters in length
    $string_match && $length_match;

} @fruits;

for my $F (@more_fruits)
{
    print "match: $F\n";
}
print "=======================================================\n";